Circuit-controlling apparatus



Oct. 7, 1941. w. M. SCOTT, JR

0 IRCUIT-CONTROLLING APPARATUS Filed Aug. 27, 1958 10 Sheets-Sheet 1 IN V EN TOR.

WILLIAM M. SCOTT,JR.

I M a!- (325% A TTORNE Y.

Oct. 7,1941. w. M. SCOTT. JR

CIRCUIT-CONTROLLING APPARATUS Filed Aug. 27, 1938 1C Sheets-Sheet 2 INVENTOR.

WILLIAM M. SCOTT, JR.

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Filed Aug. 27, 1938 10 Sheets-Sheet INVENTOR.

WILLIAM H SCOTT, JR.

A TTORNEY.

Otit. 7, 1941. w, M, SCOTT, JR 2,258,150

CIRCUIT'CONTROLLING APPARATUS Filed Aug. 27, 1938 10 Sheets-Sheet 4 INVENT OR.

WILLIAM H. SCOTT, JR.

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Oct- 1941- M. SCOTT, JR 2,258,150.

I CIRCUIT-CONTROLLING APPARATUS Filed Aug. 27, 1938 10 Sheets-Sheet 5 INVENTOR.

WILLIAM H. SCOTT,JR.

iwi-($5M A TTORNE Y.

Oct. 7, 1941. w. M. SCOTT. JR

CIRCUIT-CONTROLLING APPARATUS Filed Aug. 2'7, 1958 1C Sheets-Sheet 6 lqflo l/ z;- ww,

INVENTOR WILLIAM M. SOOTT,JR.

A TTORNE Y.

w. M. SCOTT. JR

CIRCUIT-CONTROLLING APPARATUS Filed Aug. 27, 1938 v1C Sheets-Sheet 7 INVENTOR.

WILLIAM u. scongun.

A TTORNE Y.

Oct. 7, 1941. w. M. SCOTT, JR

CIRCUIT-CONTROLLING APPARATUS Filed Aug. 2'7, 1938 10 Sheets-Sheet 8 INVENIOR.

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ATTORNEY.

Oct. 7, 1941. w. M. SCOTT, JR

CIRCUIT-CONTROLLING APPARATUS v10 Sheets-Sheet 10 Filed Aug. 27, 1958' INVENTOR.

WILLIAM SCOTT, JR.

A TTORNEY.

Patented Oct. 7, 1941 CIRCUIT-CONTROLLING APPARATUS William M. Scott, in, Bryn Mawr, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of New Jersey Application August 27, 1938, Serial N 0. 227,089

22 Claims.

My invention relates to circuit-controlling apparatus, and particularly to circuit breakers, of the type provided with disconnect contacts to permit withdrawal from a switchboard or equivalent.

In accordance with one aspect of my invention, circuit-breaker structure is supported from a vertical wall or panel of a frame by conductors which extend through the wall and on the other side thereof provide a mounting for the disconnect contacts, and the operating mechanism for the movable contact structure is mounted on the 'under side of ahorizontal wall or panel'of the frame through which extends an insulated operating member; more particularly, the framewith the aforesaid parts mounted thereon is removable as a unit from a truck, or other supporting structure, the aforesaid vertical wall or panel serving as part of the rear wall of the truck and the aforesaid horizontal wall or panel dividing the truck into an upper compartment containing the contact structure of the circuit breaker and a lower compartment containing the operating mechanism of the circuit breaker.

Further in accordance with my invention as applied to multi-pole circuit breakers, there is provided an interpole barrier assembly removable as a unit from the truck or equivalent housing for the circuit breaker and comprising panels of insulating material which cooperate when the assembly is in place with sheet-insulating material comprising or lining the aforesaid vertical and horizontal walls of the circuit-breaker framework, to define separate compartments for each pole of the breaker.

My invention further resides in the features of construction, combination and arrangement hereinafter described and claimed.

Aspects of my invention herein disclosed but not claimed are claimed in divisional applications Serial Nos. 251,500, 331,507 and 331,697.

For an understanding of my invention, reference is to be had to the accompanying drawings in which:

Fig. 1 is a front perspective view of a switchboard with a plurality of truck type circuit breakers in service position (Sheet 1) Fig. 2 is a perspective view of the rear of the switchboard of. Fig. 1 with some of its panels removed (Sheet 1);

Fig. 3 is a perspective of part of the switchboard of Fig. 1 with the truck units completely I,

withdrawn and not shown (Sheet 1) Fig. 4 is a side view insection of one of the truck units of Fig. 1 and of its associated switchboard unit' (Sheet 2);

Fig. 5 is a perspective view on enlarged scale and with parts broken away of a disconnect arrangement shown in Fig. 4 (Sheet 3);

Figs. 6 and '7 are plan views in section illustrative of the relative positions of the truck and switchboard units when their disconnect contacts are engaged -Fig. 6and disengagedFig. '7 (Sheet 4) Figs. 8 and 9 are rear and front perspective views of the truck unit of Fig. 4 (Sheet 5);

Fig. 10 is a perspective view on enlarged scale of the frame of the circuit-breaker unit of Fig. 4 (Sheet 6) Fig. 11 is a perspectiveview of an interpole barrier (Sheet 6);

Fig. 12 is a front elevation with parts broken away of an alternate form of interpole barrier in place (Sheet 4);

Fig. 13 is a detail view in side elevation of the contact structure of the circuit breaker of Fig.- 4 (Sheet 3);

Fig. 14 is a rear view of the frame shown in Fig. 10 (Fig. 6);

Fig. 15 discloses a modified back plate for the frame of Fig. 10 (Sheet 4);

Fig. 16 is a side elevational view, partly in section, and on enlarged scale of a blowout and contact assembly shown in Fig. 4 (Sheet '7) Fig. 17 is similar to Fig. 13 but with the contacts in open-circuit position and with some elements broken away (Sheet 8) I Fig. 18 is a perspective of a contact element shown in Fig. 17 (Sheet 8) Figs. 19 to 21.are perspective views of the components of a blowout assembly shown in Fig. 17 (Sheet 9);

Fig. 22 is a front elevational view, with parts broken away, showing the relation of some parts of a blowout assembly shown in Fig. 17 (Sheet 9) Fig. 23 is a side elevational view of an insulator shown in Fig. 22 (Sheet 9);

Fig. 24 is a perspective view of the core member shown inFig. 22 (Sheet 9);

Fig; 25 is a sectional view of an arc chute and blowout assembly shown in Fig. 4 (Sheet 10);

Fig. 28 is a perspective view of the arc chute of Fig. 25 (Sheet 10);

Figs. 2'7 and 28 are explanatory figures referred to in the specification in description of removal of the arc chutes (Sheet 10);

. Fig. 29, in perspective, illustrates the essential elements of circuit-breaker operating mechanism and the truck racking gear (Sheet 11);

panel Fig. 30 is a perspective view of parts of electromagnetic operating mechanism shown in Fig. 4 (Sheet 6);

Figs. 31a-d illustrate diiferent positions of elements of Fig. 29 referred to in explanation of the interlocking relations of the racking gear and the tripping mechanism.

Referring to Fig. 1, the switchboard SB is a rectangular metal-clad structure containing bus bars, cable connections, and one or more truck' or withdrawal type circuit breakers BI-Bi. The stationary structure S, Figs. 2 and 3, of the switchboard comprises units SI-SG, corresponding in number with the circuit breakers, suitably mounted in alignment with each other.

The ends E, E of the switchboard are suitably reinforced steel panels attached to the end units SI, S6 and are substantially wider than the side panels of the units. Each of, the units SI-Si consists of three compartments vertically aligned, individually covered with removable steel panels, and separated or sealed by horizontal steel barriers. Sinc all units are, or may be similar in construction, only one of them need be described. Referring to Fig. 4, the uppermost compartments I and la, of a unit 8, exemplary of any of units SI-Si, are sealed from the next lower compartment 2 by the horizontal steel barrier 3; the

upper wall 4 of the compartments I, la is a steel plate forming the top of the unit; the rear wall of the compartment I is the removable steel cover plate I; and the sides of the compartment I are formed by side plates 8 extending from top to bottom of the unit. The steel partition I isolates the two compartments I and la. from each other.

The upper compartments I, In contain auxthree bus conductors 3, 9a, so each wrapped in] phenolic insulation, molded and cured in position and clamped in the impregnated maple blocks I0, Illa (Fig. 2) to withstand short-circuit stresses. To each tubular bus is directly attached a support II for disconnect contacts I2 whose purpose and construction are hereinafter described. Each of the disconnect contact assemblies for a bus conductor is enclosed in its individual housing I3 of insulating material. The rear wall of compartment 2 comprises the removable metal panel I3 and the front wall thereof comprises the upper part of the panel I5, of insulating material and in which there are three staggered slots I6 for permitting contacts II extending from the rear of the circuit-breaker unit B to pass through the panel into the similarly staggered disconnect housings I3. Thus, when the unit B is withdrawn, it is impossible for an attendant accidentally to touch any uninsulated parts at high potential..

The bottom compartment I8 of the unit S, whose rear face is closed by the removable steel I9, contains cable disconnect contacts, suitably encased in insulating housings 2U, current transformers CT, and the outgoing cable connections therefrom. The housings are supported, as by insulators 2| from the cross brace 22, in alignment to receive the contacts 23 which pass through slots 24 in the lower part of panel I5 from the rear of the breaker unit B. The duct 25 along the front face of compartment I8 may be used to encase the wires from the transformers CT to a protective relay or electromagnet hereinafter identified. Access to the interior of duct 25 may be had by removal of the steel panel 25a.

Extending from the front of each unit (SI- S6) are the rails 26 for guiding the wheels 21 of its associated circuit breaker unit (BIB6), a pair of lugs 28 whose purpose will hereinafter be described, and a dust shield member 29 for the auxiliary contacts I. The rails 26 extend upwardly from the steel base 30 from which also extends the tripping cam 3i whose purpose will hereinafter appear.

Th steel base 30, comprising plates and structural members, extends the length of the switchboard and forms a foundation to which the units are secured.

Reverting to the arrangement providing for disengageabl connection of the bus conductors with disconnect contacts Il of the circuitbreaker unit B, the support II for the bus disconnect contacts I2 comprises two members Ila, Ilb (Fig. 5) of metal which are clamped by bolts 32 directly to the bus conductor 9. From the front of member II'b extend the brackets 33 for supporting the pins 34, 35 upon which the upper a two yoke members.

The upper equalizing yoke 38 presses downwardly on the upper face of two adjacent upper contacts I2; a similar yoke (not shown) bears against the under faces of the corresponding pair of lower contacts I2. The pin 39 passes loosely through forward ends of all of the upper contacts I2 and similarly pin 40 passes loosely through the forward endsof all of the lower contacts I2. This contact construction, more fully described in United States Letters Patent #2,029,028 to Kneass et al., insures equal distribution of the contact pressure between contacts I2 and I1 notwithstanding their appreciable misalignment.

The housing I3 which is assembled about the bus disconnect structure after the latter has been clamped to the bus conductor comprises two separable parts held together as by screws 4|. Across the open front end of the housing extend two pivotally mounted shutters 42 of insulating material biased toward engagement with each other by springs 43. The gap between the forward edges of the shutters is in alignment with the corresponding slot I6, Fig. 4, in thepanel' I5. When the circuit-breaker unit B is pushed into position, each of the disconnect contacts I1 enters its corresponding slotIS, separates a pair of shutters l2, and slides between the upper and lower disconnect contacts I2. When the unit B is completely withdrawn, the shutters 42, 42 within each housing I3 close the corresponding panel slot I 6 and preclude accidental contact with th disconnect contacts I2.

As more apparent from Fig. 2, the bus conductors and live parts connected thereto are completely insulated and effectively isolated from each other. The bus conductors, as previously stated, are encased in insulation except within the insulating housings l3, and each disconnect contact assembly is within its individual housing It s of insulation. When panel I4 is opened, there is,

therefore, no possibility of accidental contact.

with any of the live parts within compartment 2. Moreover, as shown in Figs, 6 and 7, the sides I, I of the unit 8 so far overlap the sides of the circuit-breaker ,unit B that it is not possible for an attendant to touch the contacts 11 until after the unit B has been so far withdrawn from the switchboard that contacts l1 are out of engagement with the live disconnect contacts 12.

Each of the truck units BIB8, exemplified by unit B, Figs. 4, 8 and 9, is a substantially rectangular structure formed by angle iron and sheet steel suitably joined as by welding. The door 44 which permits access to the circuit-breaker mechanism hereinafter described is provided near the top with a louvered opening 45 to permit escape of gases incident to circuit interruption and allowcirculation'of air for cooling. In the particular construction shown in Figs. 4, 8 and 9, the top of the truck structure is closed by a sheet metal wall 48.

. The circuit breaker and its operating mecha- Ina modification shown in Fig. 12, the top panel 46 of the truck is omitted, and the interpole barrier unit 62a withdrawn and inserted through the opening thus aflorded.' In this nism is removable as a unit from the rear of the truck structure. The framework 51 of the unit, shown in Fig. 10, comprises a sheet-steel and angle iron structure having a vertical 'wall 41 and a horizontal wall 48 connected and braced by gusset plates 49 having therein holes 50 to receive-crane hooks. Holes 50 are approximately in line with the center of th gravity of the unit to facilitate its manipulation while suspended from a crane.

When the unit is in position, its wall 41 serves as the lower part of the rear wall of the upper or circuit-breaker compartment of the truck; the upper part of the rear wall of the truck compartment is an integral part of the truck structure.

The frame 5| is slidable along and supported by the angle irons 52 extending across the sides of the truck and is held in position by bolts 53 (Fig. 4) which pass through the angle pieces 54 projeetingrearwardly from the rear wall 41 of the frame 5|. racking links hereinafter described.

The upper face of the horizontal panel-48 and the front face of the vertical wall 41 ar covered The brackets 55 serve to guide modification. the top of the interpole barrier unit is left open and the front panel 64A thereof extends from top to bottom. The metal grills 45a within and near the top of each compartment formed by panelsil, 51 and 58 serve to chill the arc gases.

The circuit breaker shown herein is a threepole breaker but since the construction ofall three poles are similar, only one need be described. Referring to .Figs, 4, 13 and 17, the upper main contact assembly" 65 comprises a stud 85 which passes through the sleeves 61, 88 of insulating material. By tightening nut 10 on stud 88, the two sleeves 61, 88 are forced tightly against opposite sides of the vertical wall 41 of fram 51. Similarly, the lower main contact assembly 1| is mounted upon a stud 12 which passes through sleeves 13, 14 of insulating mate rial. Bytightening nut 16, the sleeves 13, 14 are clamped to opposite sides of the rear vertical wall of the frame 5|. I

The disconnect contacts I1, flare held to the studs 66, 12 by the nuts 11, 18, respectively. The

or lined with the panels 51, 58 of insulating ma terial. -The strips 59 of insulating material projecting upwardly from panel 51, and similar strips extending forwardly from panel 58form slots I for receiving the bottom and rear edges of the panels 8! of an interpole barrier unit 62, Fig. 11. The rear wall of the truck is internally faced with a panel 58a of insulation which is, in effect, a continuation of panel 58 and from it project the strips 60a of insulation which are, in eifect, continuations of the strips 60. The top of the the upper, forward parts of the isolated compartments formed by the panels GI, 54, 51 and 58 open for discharge of arc gases. Preferably, short horizontal ledges 64b project inwardly of the compartments from or adjacent the upper edge of panel 64 to prevent the arc gases from flowing downwardly and adjacent the parts of the circuit breaker, and within each compartment above upper end of each of the disconnect contacts I1 is braced by an (insulator 19, Fig. 8, to resist bending during insertion and withdrawal of the circuit-breaker unit B from the switchiboard. The insulators 19 are secured to and project horizontally from the rear face of the upper part of the steel wall 41 of frame 5|.

Preferably, the portion of wall 41 which supports insulators 19 lies in a plane farther to the rear than the plane of that portion of the wall from which th studs 66, 12 extend. The uppermost portion of wall 41' is provided with a series of holes 80, Fig, 10, through which pass screws 8|, Fig. 4, for securing it to the rear face of the shown-in Fig. 13. Between each pair of rings 82,

the plate 41 is provided with a slot 83 to eliminate or minimize eddy currents. For plate 41a may be substituted the plate or casting 41b, Fig.

15, entirely of bronze or other suitable non-magnetic material provided with openings 82!: which fit the insulating sleeves 61, 13.

The main contact assemblies 65 and 1| are mechanically interconnected by the insulator 84 which resists forces, due to flow of heavy curv rents, tending to move assemblies away from each other. The insulator 85 mechanically connected to the frame member 86 of assembly 1| andtothe base plate 48 of the unit frame 5| stiifens or supports the assembly 1| against forces orv shocks incident to the opening and closing movements of the parts of the circuit breaker.

The upper main contact assembly, Figs. 4, 13 and 16, comprises the main contact member 81, the auxiliary contact member 88, the arcing horn 99, the arcing tip 90, and blowout coil 9I. The auxiliary contact 88 is biased to the position shown in Fig. 13 by a spring 88a and connected by pigtail 92 to the main contact. A pair of links 93 on opposite sides of contacts 81, 88 support and guide the latter during its movement.

The arcing horn 89 is mechanically connected to the main contact 81 by bolts 94, 95, Fig. 16, which pass through sleeves 95, 91 of insulating material and clamp the front and rear ends of the horn against the plates 98, 99 of insulating material. It is necessary to anchor both ends of the horn to prevent its deformation when the blowout coil is traversed by heavy short-circuit currents. The arcing tip 90 is supported from the rear face of the forward end of horn 89 and biased toward engagement with-the end of the horn by spring I00. During tripping of the breaker, this biasing force is supplemented by the effect of the electromagnetic field produced by current through the tip 90 and the contact II hereinafter described. Pigtail IOI connects the movable arc horn tip 90 to the horn 09 to divert most of the current from its pivot. The current flowing in this pigtail forces the shunt contact toward engagement with its complementary contact.

One end of the blowout coil 9I wound upon core I02 is held in electrical connection with main contact 81 by the bolt 95 and the other terminal of the coil is held, in electrical connection with the arcing horn structure by the bolt 94. Electrical connection of the horn 89 with contact 81 except through the blowout coil is precluded by sleeves 96, 91 and plates 90, 99. The coil is wound from heavy flat wire or ribbon covered with insulation resistant to the effects of high temperatures.

The lower, main contact assembly 1i, Figs. 4, 13 and 17, comprises the stationary frame member 86 within which is pivotally mounted the movable frame member I03 connected by pigtail I04 to the stationary frame member and to the bridging contact member I05 loosely pivotallymounted in the movable frame member I08. The contact member I05 is made of two side pieces I05a of copper sheet spaced by and welded to the blocks I05b; the holes through the member for the pivot pins connecting it to the frame I00 and the rod I05 are preferably bushed with hardened steel bushings I050. The rod I00 (Fig. 17) pivotally connected to the bridging contact member I05 near the upper end thereof passes through the split tubular structure I01 and through the plug I08 threaded into the outer end thereof. Bolts I09 may be tightened to clamp the split housing I01 upon the plug I08 and so hold it in the position affording the desired compression of spring IIO disposed between plug I00 and a shoulder on the rod I00. The nuts III on the free end of rod I00 serve as a stop limiting the extent of its forward movement when the circuit breaker is open.

The upper contact piece II2 of the bridging contact member I05, Figs. 17 and 18, engages the upper main contact 81 in a vertical plane and the lower contact piece IIO engages the lower main contact 1Ia in a horizontal plane. During closure of the circuit breaker, the contact II2 engages contact 88 and causes member I05 to pivot about pin II4 to effect wiping engagement be- .tween the lower movable contact 0 and stationary contact Ho. The engagement of these lower contacts and continued movement of frame I00 causes member I05 to move upwardly and insure wiping engagement between the upper contween the upper contacts H2, 08 and another component acting at right angles thereto to determine the contact pressure between the lower contacts H0 and Ho. This construction is in general similar to but an improvement of that disclosed and claimed in my copending application Serial #151,359.

Preferably, a dust shield IIOa, Fig. 13, is attached to the bridging member I05 partially to enclose the lower contact 'I I0.

To the upper end of movable frame member I00 is attached the arcing contact II5 which, when the circuit breaker is closed (Figs. 4 and 17) engages both the auxiliary or shunt contact 00 and the movable arcing horn tip 00. Preferably contacts I I5, 00 and 90 are of Elkonite" or similar arc-resistant material. When the circuit breaker is tripped the contact H5, in moving to its fully open position, Fig. 13, separates fromthe auxiliary contact 00 thus to include the blowout coil 9I in circuit. Shortly after separation of contact II5 from the horn tip 00, the arc extends from the horn 09 to arcing tip I ll of the movable arc contact I I5 until the tip I I0 moves sufficiently close to the tip II1 of a second, stationary arcing horn IIO connected by bolt 00a to the frame 00 and at the same potential as tip IIO. When the arc transfers from the tip I I1 to the upper arcing horn I I9, a second blowout coil I20 is included in circuit further to force the arc upwardly in the arc chute hereinafter described and further to separate the terminals of the arc.

The construction of the front blowout assembly I2I comprising the upper and lower arcing horns II 8, H0 and coil I20 is more clearly understood from Figs. 19 to 25. When the upper horn III, Fig. 21, and the lower horn, Fig. 19, are in their assembled position, they provide a housing or casing for the blowout coil I20 (Fig. 25) one terminal I22 of which is held in electrical contact with the upper horn III by bolts, not shown, which pass through insulating sleeves and washers, through holes I20 in the lower horn III, and holes I24 in terminal I22 to thread into the under face of block I25 integral with the upper horn II9. Similarly, the other terminal I20 of the blowout coil I20 is held in electrical contact with the lower horn IIO by bolts I21, Fig. 1'7, which pass through insulating sleeves and washers, holes I20 in the lower horn III, and holes I20 in coil terminal I20 to thread into the under face of projection I00 of the upper horn The core IOI for the blowout coil is preferably formed by winding a strip of'thin sheet iron to the blowout coil M8 clamps it against the pole pieces I85 held against the outside faces of the side panels 588 oi the arc chute. Soft rubber gaskets between the inner ends of the insulators and horn members reduce and distribute the mechanical strain on the insulators sufficiently to avoid brealrage. The pole pieces I48, which may be laminated, for the rear blowout coil 8? are also held, as by bolts 8a, against the out side faces of the side panels. The slots Mi in the rear pole pieces I48 are suited to receive the bolt I48 which passes through the core I82 of the rear blowout coil. By loosening the nuts on bolts I42, 88s, the arc chute and front blowout assembly may he slid forwardly from the circui breaker contact, structure and out of the truck through its door 88.

- The side panels I88 and end panels I48 of the arc chute are of suitable insulating material; for example, the sides E88 may be of sheet asbestos and the ends 888 of fibre or the like. Within the arc chute above the arcing horns are four groups of spaced plates 544 of insulating material, for example fibre, which serve to split the arc lengthwise as it rises in the chute and as a source of arc-quenching or deionizing gases. The plates of each group are suitably separated as by spacers I45 (Fig. 25) and held in position by bolts I48a. If the arc rises above plates I44, it is lengthened and split into a large number of arcs in series by the series of copper plates I41 spaced and insulated from each other in the top of the arc chute. These plates serve to quench, mullie, and chill the gases of the arc. Their construction and arrangement is similar to that disclosed and claimed in United States Letters Patent #2980582 to Graves.

To facilitate withdrawal of the arc chutes from the truck, each of them is provided (Figs. 4, 25 and 26) with a pair of plates I48 held to the sides I88 of the chute and having holes I48 in their upper ends to receive the ends of an inverted U-shaped link I 58 suspended from and siidable along the guide bars II suitably attached to the under face of the top wall 46 of the truck structure. when the in'terpole barrier assembly 62 is in place, the links I 58 rest upon the top wall 83 of the barrier assembly-(Figs. 4 and 2'1), but when the barrier assembly is removed, the links I58 swing downwardly each above its associated .arc chute I88 (Fig. 28) so that the lower ends thereof may be hooked into the holes I48 of the plates I48 of the arc chute.

To assist in alignment of the arc chutes I86,

the rear upper end of each of them is received by the notch I52 in the plates I58 of insulation iii (Figs. 4 and 10) which project forwardly from the front face of the vertical wall 41 of the supporting frame for the contact structure of the circuit breaker. j

All of the operating mechanism for the circuit breaker is supported from the under face of the horizontal wall 48 of the frame H and the only position by spring I84.

of the circuit breaker and the lower end of each (Figs. 4 and 29). All ofthe operating arms I51 are secured to shaft I58 supported intermediate its ends by a pair of split bearings I58 (Fig. 30),

one on each of the side plates I62.

The coil I68 which may be energized to effect closure of the circuit breaker is within a housing i8l (Figs. 4 and 30) having two sides formed by steel plates I62 which are attached to and depend from the wall 48 of frame 8i and two sides formed by steel plates I68 which extend be tween, and secured, as by welding, to plates i68. Plates 562, in addition to serving as sides of the ooh housing and as bearing plates for shafts of the operating mechanism, also provide feet upon which the circuit-breaker unit may rest when withdrawn from the truck.

The rear wall of the coil housing is formedv by the steel plate I64 held in place by screws I65 which pass through plate I64 threadably to engage blocks I66 welded to the inner rear corners of the housing. The front wall of the coil houslug comprises steel plate I61 welded in place and provided with an opening to receive the guide tube I 68 of non-magnetic metal for the movable core or armature I88. The rear end of the guide, tube which supports the coil I68 is received by a circular recess I18 in the rear wall I64 of the coil housing. The stop I'll for limiting the forward movement of the core I68 comprises a plate vend of toggle link 16 is pivotally connected by pin I11 to that one of the arms I61 which is attached to the central portion of shaft I58 between the plates I62 which support most of the circuit-breaker operating mechanism. The lower end of toggle link I15 is pivotally connected by pin I18 to a bell-crank lever I18 whose pivot pin I88 provides a fixed axis for angular movement of lever I18. The ends of pin I88 are supported byplates I62. I

The arm I8I of lever I18 is engageabie near its free end by the latching member I82 secured to shaft I88 and biased to its latching When coil I85 of the tripping magnet I86 is sufficiently energized, as upon occurrence of an overload, the movement of its armature I81 through arm I88 rocks shaft I88 in counterclockwise direction to release the latch I82, whereupon powerful springs I88 (one of which is shown) rocks the shaft I58 to open the circuit breaker.

All of the stresses incident to opening and closure of the circuit breaker are confined to the frame 5| and are not transmitted from one operating part to another through the truck Moreover, since the operating mechaframe.

. nism in its entirety is part of the circuit-breaker unit, it may readily be assembled and tested as a completely operative unit prior to mounting. in the truck. Preferably the kinetic energy of the moving operating parts is absorbed by a friction brake B similar to that disclosed and claimed in United States Letters Patent No. 2,137,001. i

The circuit breaker may be tripped manually by depressing the forward or handle end of lever I90 which is pivotally mounted within a housing or bracket I9I secured to the front end of the frame -I. The handle of lever I90, as shown in Figs. 1, 4 and 9, projects through a slot I90a in the door 44 of the truck. When the handle is depressed the extension I02 of lever I00 engages the extension I93 of latch I82 to effect its release from arm I8! and so permit springs 89 to open the circuit breaker.

The circuit breaker may be reclosed manually by inserting a bar I94 through an opening I85 (Figs. 1 and 9) in the truck door and into the slot i536 of a disk l9! loosely mounted, between the sides of bracket ISI, on the shaft I98 (Fig. 29). A link I95 connects the disk I0! to the toggle pin Ht. After the bar I94 is so inserted, it is swung downwardly through an arc of about 90 and so moves pin I'll to the left thus to rock the shaft i58 in clockwise direction to on the rods th t and so effect circuit-closing movement of the movable contacts of the circuit breaker. If an overload exists, the circuit-breaker cannot be held closed by her i8 because when the latch $22 is released, the toggle collapses and springs it are free to open the circuit breaker regard less of the position of disk i'0'l. The construction and operation of the operating mechanism is similar to that disclosed and claimed in Reissue Patent #19,753 to H. G. Graves.

Preferably, the edge of disk 119?, which is visible through opening 95 in the truck door 14 is colored or otherwise marked to indicate whether the circuit breaker is in open or closed circuit position. The disk l 91 is biased by spring 200 to the open circuit position so that it will move to that position when bar E94 is removed or released after tripping oi the breaker during manual closure thereof. Spring 200 also restores the arm idl to its latching position after tripping of the circuit breaker in readiness for the subsequent re-setting of the toggle incident to automatic or manual reclosure of the circuit breaker.

From the tripping lever I90 is suspended the rod 206 which extends through the base of the truck in line with the cam 3I on the base of the switchboard to trip the circuit breaker, if it be closed, as the truck is pushed into the switchboard.

The bar 202 pivotally suspended from armi5'la on the operating shaft I58 of the circuit breaker is utilized to operate the auxiliary switches 203 mounted upon the panel 204 suitably mounted in the lower compartment of the truck. These switches may be used to operate signal lights or perform other control functions in accordance with the position of the circuit breaker.

Each truck unit BIB6 is locked in its innermost or normal position by a pair of racking bars 205 (Fig. 4) each having a hooked end which drops over and engages the pin 208 of one of the pair of abutment members 28 at tached to the front face of each of the switchboard units SI-S6; the rear face of the hooked end is suitably sloped so that if it is down when the truck is pushed into the switchboard the engagement of the sloping end with pin 200 causes the bar to lift and drop over the pin.

The other end of each bar 205 is pivotally connected to a crank arm 20'! secured to shaft I00 to which is secured the notched disk 200 accessiin bearings I900 in brackets integral with frame M, Fig. 10. I

To release bars 2l5.from pins 200 and move the truck B to such extent from the switchboard unit S that all circuit connections between them are broken, the shaft I0! is rotated a half revolution from the position shown in Figs. 29 and 31a. To effect this movement, a bar or rod I0 is inserted by the operator in the notch 20. of disk 208 substantially in alignment with the stop IOIa defined by the lower edge of housing ISI and then swung upwardly, through an arc of about 90, until arrested by stop I8Ib defined by the upper edge of housing IBI; the bar Ifla is then removed and reinserted in notch 200D of disk 208 and again moved upwardly through an arc of somewhat less than 90. Throughout substantially all of the resultant movement of cranks 201 effected by the two-step racking movement of bar I94a, the rear ends of the bars 205 remain, in engagement with and press against the abutments 28 so that the counterclockwise rotation of the cranks 201 from the position shown in Fig. 31a to the 180 displaced position shown in Fig. 31a effects a forward movement of the truck B. Somewhat before completion of the 180 movement of cranks 201, the bars 2" rest intermediate their ends upon the abutments 209 so that further movement of the cranks in the same (counterclockwise) direction causes the bars 205 to pivot about the abutments 20! and so lift their hooked ends free of the pins 200.

When the circuit-breaker unit B is in its normal or service position shown in Fig. 4, the disk 208 is in the position shown in Fig. 3m with its notch 2080 receiving the upper end of the verticaily slidable pin 2I0 which is plvotally mounted upon the manual tripping lever I biased to non-tripping position by spring 2! I. The notch 2080 and notch 208d for the pin 2I0 are out of the plane of the notches 2000, 200!) so that, except when the pin 2I0 is received by one or the other of notches 2000 or 20041, it is impossible to close the circuit breaker. Before the circuitbreaker truck can be moved from the position shown in Fig. 4, and before disk 208 can be moved from the position shown in Fig. 31a to the displaced position shown in Fig. 31b, the handle I00 must be depressed thus to insure the circuit breaker is open before the disconnect contacts I! of the truck 3 separate from the disconnect contacts I2 of the switchboard.

To provide a test" position in which the circuit breaker, while its main contacts are out of circuit with the bus conductors, can be operated by control circuits through the contacts 0, the disk 208 is provided with a flattened cam notch 208d into which the pin 2I0 of the trip lever I90 rides (Fig. 310) as the disk 200 approaches the end of its aforesaid second 90 movement. Engagement of the pin 2I0 with the shoulder 2I2 can be felt by the operator who is thus informed the truck has reached the test" position. In this position the circuit breaker can be opened and closed either automatically or manually, and operation of its parts observed without danger to the operator and without need completely to withdraw the truck from the switchboard.

the truck. The ends of this shaft are supported With the circuit breaker truck in test" position and the circuit breaker closed, the breaker must be tripped manually before the lever Illa can further be raised to complete the second 90' movement of the disk 200 (from the position shown in Fig. 31b to the position of Flg. 3111).

The disclosed construction of disk 200 and its aasaico relation to pin 2") also prevents the circuitbreaker from being closed when the truck is moved-from "test position toward the switcha To summarize, the interlock between the rack=- ing and tripping mechanisms prevents closure of the circuit breaker for truck positions intermediate the service and test positions, determines the test position during withdrawal of the truck from the switchboard, prevents accidental withdrawal of the truck from test position, and effects tripping of the circuit breaker, if closed, as the truck is moved from "test toward "service positions.

What I claim is:'

1. A circuit breaker comprising a frame including two panels disposed in angular relation to each other, contact structure comprising rela tively movable contact members, means for sup- 5. A circuit breaker comprising a frame including two panels disposed in angular relation to 1 each other, main contacts within the angle between said panelsspaced from one of said panels by sleeves of insulation, conductors passing through said one of said panels and said sleeves to provide for external connections to said con tacts and to clamp said sleeves to said one of said panels, a movable contact adapted to bridge porting said contact structure from said frame within the angle defined by said panels comprising conductors extending through one of said panels, operating mechanism, means for supporting said mechanism from said frame, and an insulated operating member extending through the other of said panels fromv said operating mechanism to said contact structure to effect relative movement of said contact members.

2. A circuit breaker comprising a frame including two panels disposed substantially at right angles to each other, contact structure comprising relatively movable contact members, conductors extending through one of said panels for supporting the contactstructure of the'circuit breaker within the angle between the panels, operating mechanism, means for supporting said mechanism from the other of said panels, and an insulated operating member extending through said other of said panels from said operating mechanism to said contact structure to effect relative movement of said contact members.

3. A circuit breaker comprising a frame including two panels disposed in angular relation to each other, main contacts supported from one of said panels in the angle between the panels by conductors extending through said one of them, a movable contact for bridging said main contacts and supported from one of them, operating mechanism, means for supporting said mechanism from said frame, and an insulated operating member extending through the other of said panels mechanically to connect said operating mechanism to said movable contact.

4. A circuit breaker comprising two panels disposed in angular relation to each other, conductors extending through one of said panels for supporting contact structures of the circuitv ing said mechanism to said movable contact structure.

said main contacts, operating mechanism, means for supporting said mechanism from said frame, and an insulated operating member for said movable contact extending through the other of said panels from said operating mechanism.

6. A circuit breaker assembly removable as a unit from a switchboard comprising a frame having a vertical panel and a horizontal panel, disconnect contacts disposed to the rear of said vertical panel, main contacts disposed on the other side of said vertical panel, conductors extending through said vertical panel to connect said disconnect contacts to said main contacts and to support all of them upon said panel, a bridging contact pivotally mounted on one oi said main contacts, an operating member therefor extending through said horizontal panel, and operating mechanism for actuating said operating member supported by and disposed below said horizontal panel.

7. A circuit breaker assembly removable as a unit from a switchboard comprising a frame having a vertical panel and a horizontal panel, disconnect contacts extending from the rear face of said vertical panel, main contact structure supported from the front face of said vertical panel, a movable contact adapted to bridge said main contacts, electromagnetic operating mechanisrn for said movable contact supported from the under side of said horizontal panel, and an insulated operating member extending from said mechanism through said horizontal panel to said movable contact.

8. An enclosed truck-type circuit breaker including a circuit breaker assembly removable as a unit from the truck housing and comprising a frame having a horizontal panel for dividing the interior of the truck housing into upper and lower compartments and a vertical panel forming part of the rear wall of the truck housing, disconnect contacts extending from the rear face of said vertical wall, main contact structure within said upper compartment supported from said frame, contact structure movable within said upper compartment to bridge said main contacts, operating mechanism for said movable contact structure supported within said lower compartment from the underside of said horizontal panel, and a connecting member extending through said horizontal panel to connect said movable contact structure to said operating mechanism.

9. An enclosed truck type circuit breaker including a circuit breaker assembly removable as a unit from the truck housing and comprising a frame having a horizontal panel for dividing the interior of the truck housing into upper and lower compartments and a vertical panel forming part of the rear wall of the truck housing, disconnect contacts extending from the rear face of said vertical wall, main contact structure within said upper compartment supported upon 'said frame, contact structure movable within said upper compartment to bridge said main contacts, operating mechanism for said movable contact structure supported within said lower compartment from the underside of said horizontal panelfa connecting member extending through said horizontal panel to connect said movable contact structure to said operating mechanism, and means operable from the front of the truck to actuate said operating mechanism.

10. A multi-pole circuit breaker assembly comprising a frame having a vertical panel and a horizontal panel, means for supporting the main stationary contact structure of each pole from said vertical panel in vertical alignment, a plurality of contacts each movable to engage the main contact structure of a pole of the circuit breaker, individual insulated operating members extending from said movable contacts through said horizontal panel to the other side thereof, and a common actuating member for said operating members disposed on said other side of said horizontal panel.

12.1; multi-pole circuit breaker comprising two panels disposed in angular relation to each means for supporting the main stationary Contact structure of each pole from one of said panels, an interpole barrier assembly removable as a unit irom the circuit breaker and comprising leis coactlng with said first-named panels to r de isolated compartments for the main conucirore of each pole, a plurality of contacts ovable within one said compartments,

2g frame having a vertical panel and a cntal panel, means for supporting the main tacts of each pole from said vertical panel m vertical 3 'gnrnent, a plurality of contacts each movable to bridge the main contacts of a pole or the circuit breaker, individual insulated operating members extending from said bridging contacts through said horizontal panel to the other side thereof, and a common actuating m mber for said operating members disposed on other sideof said horizontal panel.

A multi-poie circuit breaker comprising two panels disposed in angular relation to each other, means for supporting the main contacts of each pole from one of said panels, an interpole barrier assembly removable as a unit from the circuit breaker and comprising panels coacting with said first-named panels to provide isolatedcompartments for the main contacts of each pole, a plurality of contacts each movable within one of said compartments to bridge the pole contacts therein, and individual operating membars for said movable contacts extending through the other of said first-mentioned panels into the respective pole compartments.

14. A multi-pole circuit breaker comprising individual arc chutes and blow-out coils for the contact structure of each pole of the circuit breaker, and an interpole barrier assembly removable as a unit from the circuit breaker and independently of said arc chutes comprising panels defining cells each of which contains the contact structure of a circuit breaker pole and its associated arc chute and blow-out coil.

15. A truck-type multi-pole circuit breaker including a circuit breaker assembly removable as a unit from the truck and comprising the fixed and movable contact structure of the circuit breaker and the operating mechanism for said movable contact structure, and an interpole barrier assembly removable as a unit from the truck comprising panels defining cells each of which contains the contact structure of one pole of the circuit breaker.

16. A truck-type multi-pole circuit breaker including a circuit breaker assembly removable as a unit from the truck and comprising the fixed and movable contact structure of the circuit breaker and the operating mechanism for said movable contact structure, individual arc chutes for the contact structure of each pole of the circuit breaker, and an interpole barrier assembly removable as a unit from the truck comprising panels defining cells each of which contains contact structure of a circuit-breaker pole and its associated arc chute.

17. A truck-type circuit breaker including an assembly removable as a unit from the rear of the truck comprising a frame, main contact structure supported by said frame, operating mechanism for movable contact structure of said circuit breaker supported by said frame, and racking gear supported by said frame including means operable from the front of the truck, when said assembly is in position, to efiect movement of the truck.

18. An enclosed truck-type circuit breaker including a circuit breaker assembly removable as a unit from the truck housing comprising a frame having a horizontal panel for dividing the interior of the truck housing into upper and lower compartments, and a vertical panel forming part oi the rear wall of the truck housing, circuitbreaker contact structure supported within one of said compartments by conductors extending through said vertical wall, disconnect contacts mounted upon said conductors exteriorly oi the truck, and operating mechanism for the movable contact structure within the other of said compartments supported by said horizontal panel and operable from the front of the truck.

19. A circuit breaker comprising a rigid frame including two supporting structures disposed substantially at right angles to each other and braced by interconnecting structure, contact structure including a movable contact member supported by said frame within the angle defined by said supporting structures, electrical terminals extending from said contact structure outwardly through one of said supporting structures, an operating member for actuating said movable contact member extending outwardly through the other of said supporting structures, and operating means supported by said other of said supporting structures externally of said angle for effecting actuation of said operating member.

20. A circuit breaker comprising a rigid metal frame including two metallic supporting structures disposed substantially at right angles to each other and faced within the angle formed by them with insulation, contact structure including a movable contact member within said angle, means for supporting said contact structure from said frame comprising terminal conductors extending outwardly through one 01' said supporting structures, operating means supported by the other of said supporting structures externally of said angle, and an operating member for said movable contact member extending outwardly through said other of said supporting structures to said operating means. I

21. A stationary housing, contacts within said housing, a second housing movable toward and from said first housing, a circuit-controlling device within said movable housing, contacts for said device extending from said movable housing for engagement with said first-named contacts, and complementary structures comprised In said housings overlapping to prevent access to said second-named contacts during their engagement with said first-named contacts.

22. A truck type circuit breaker comprising guide members extending along opposite sides of the truck, and an assembly siidabie along said guide members for removal from and insertion into the truck as a unit comprising a frame, circuit breaker contact structure, means for supporting said contact structure from said frame, mechanism for operating said contact structure, means for supporting said mechanism from said frame, racking gear operable from the front of the truck, when said assembly is in inserted position, to efiect movement of the truck, and means for supporting said racking gear from said slidable frame.

WILLIAM M. SCOTT, JR. 

